On low heat in a small saucepan, heat oil and 2 sprigs of chopped rosemary leaves. Once oil and rosemary start to sizzle, remove from heat and cool to room temperature (can be done 4 days in advance). Whisk 1/4 cup of rosemary oil and vinegar, marinate chicken pieces for 30 ? 60 minutes. Reserve balance of oil for later use.

Remove chicken pieces from marinade and lightly season with salt and pepper. Wrap each small piece of chicken with a slice of prosciutto. Alternate the chicken and sausage on the skewers, placing a sage leaf between them. Each skewer should have about 2 pieces of chicken and 2 pieces of sausage make 12 ? 13 skewers. Refrigerate the kebabs until ready to cook, to keep the fresh sausage from getting too soft (can be made ahead up to this point).

Use 2 rosemary sprigs as a brush to coat the skewers with rosemary oil and use to baste as needed during cooking. With a hot grill, create a low heat section and cook skewers over low heat and turn frequently to avoid burning, about 5 minutes on each side. Alternatively, the skewers can be cooked in the broiler until they are browned. Brush with rosemary oil if meat appears dry during cooking